is a global front end option that specifies an expression to be dynamically updated whenever the front end is running.
- FrontEndDynamicExpression->Dynamic[expr] causes the expression to be tracked and updated in the usual way, except that expr is not displayed anywhere.
- FrontEndDynamicExpression can be set using SetOptions[scope,FrontEndDynamicExpression->Dynamic[expr]], where scope can be $FrontEnd or $FrontEndSession.
- FrontEndDynamicExpression can also be set using the Option Inspector (Format ▶ Option Inspector).
Introduced in 2010